1. Technical Field
The present invention relates in general to offshore drilling rig riser tensioners and, in particular, to an improved system, method, and apparatus for corrosion-resistant riser tensioner cylinder rods having an outer sleeve retained with an annular layer of epoxy.
2. Description of the Related Art
Some types of offshore drilling rigs utilize “push-up” or “pull-up” type riser tensioners. The riser tensioner incorporates cylinder rods to maintain tension on the riser. The cylinder rods are subjected to a very corrosive environment caused by exposure to drilling muds, completion fluids, and general offshore environments. As a result, the rods currently being used are made from either a solid nickel-based alloy or a laser-clad cobalt-based layer that is applied to a steel alloy rod. Both of these current rod options are expensive and, in the case of cladding, result in long lead times with multiple process requirements in geographically remote locations. Consequently, there is a higher probability for damaged parts and scrap or scrappage. Thus, an improved design for riser tensioner cylinder rods would be desirable.